Anticombustion process



Patented May 23, 1933 1 'UNITED STATES PATENT OFFICE ALrHoNs O. JAEGER,or GRAFTON, rENNs LvANrA, AssmNoa, BY MESNE ASSIGN- .MENTS, TO THESELDEN RESEARCH & ENGINEERING CORPORATION, or PITTS- I BURGH,PENNSYLVANIA, A CORPORATION or DELAWARE ANTIcoMBUsTIoN rnocnss NODrawing.

normally carried out at temperatures below ignition ten'iperatures inthepresence of cat alysts or contact masses which permit the process to becarried out at temperatures considerably below those encountered in. or-

, dinary combustion. In my copending ap- "plication, Serial No. 196,393,filed June 3, 1927, have described processes for the partial oxidationof organic compounds'or selective oxidation of impurities wherein theaction of the contact mass is stabilized by strongly basic earth metals.The effect of these compounds when used in conjunction .with an.oxidation contact mass is to lower its, tendency to produce totalcombustion and, therefore, to minimize losses from this source. I havefound that this anti-combustion property of the compounds of the alkaliforming metals can be used not only to reduce the tendency of combustionin a partial catalytic oxidation but also to stop ordinary combustionwhich has been accidentally started orffto prevent combustion :fromstarting. In other words, the alkali forming metal compounds may beconsidered as anti-combustion catalysts and as such can be used both forextinguishing and preventing fires. V V

I .VVhen used as a fire extinguisher the compounds are preferablyapplied to theseat of combustion in a finely distributed form,

for example in solution or suspension in liquids which possess fireextinguishing properties or which will not support combustion. Thus, theeffectiveness of water is greatly increased by dissolving, in itcompounds of the alkali forming metals which act as anti-combustioncatalysts when sprayed onto a fire. Excellent results are also obtainedby dispersions of the antithe' addition thereto of compounds of thealkali metals, alkaline earth metals and Application filed July 7, 1828.Serial No. 291,143.

combustion catalysts in non-aqueous fire extinguishing fluids, such ascarbon tetrachloride and the like. In some cases it is not readilypracticable to dissolve the alkali forming metal compounds in some ofthe pounds of the alkali forming metals. It

should be understood that the present in vention has nothing in commonwith the fire proofing processes in which ammonium or similar salts havebeen used which decompose at elevated temperatures with the absorptionof large quantities of heat with or without the evolution of gases whichwill not support combustion. The present inventi'on is based on thecatalytic action of compounds as such and not on their heat absorptionor on their evolution of blanketing gases. I

A particularly important field of utility of the present invention liesin its use for the prevention of accidental conflagrations when crudeorganic materials are being heated or,

sublimed; thus, for example, when crude phthalic anhydride from thevapor phase oxidation of naphthalene is subjected to prolonged heatingfor condensation or polymerization of quinonoid impurities or subjectedto sublimation in order to separate its constituents, there is aconsiderable fire danger as it is not economically feasible to carry outall of these processes in an atmosphere of an inert gas. The materialwill usually also contain small amounts of iron oxide or similar metaloxides which act as combustion catalysts and even though the temperaturemay be far below the ignition point fires sometimes arise from theaccidental presence of small amounts of combustion catalysts. If,however, a small percentage, which may range from a half a percent up toas much as 8 or 10%. of an alkali form ing metal compound is distributedthroughout the phthalic anhydride, the combustion ly diyidied'ioiinfThephthalic anhydride is tlienj subjectedto prolonged heating inor activityof combustion catalysts present is completely damped or stabilized sothat'fires do not tend to arise.

A similar important field lies in the heating of other products ofpartial oxidation such as-,ifor example, "anthraquinonef, maleic acid,naphthalic anhydride, and'thelikeI A further field of great economicimportance l ies in-v distillation of coal tar or ,of its fractions andparticularly. sublimation aof fractions, such as napthalene; anthraceneyand the like. Coke products are almost always present and it has beenfound that finely divided carbon is an excellent combustion catalyst.WVhen ho veveiyalka-li form ing compounds are present in sufficientamounts the combustion activity of any-combustion catalysts present isdamped '01 reg moved completely and distillations' andparticularlysublimations which hitherto have always presented a danger of fire canbe carried out with a maximum of safety by' using the principles of thepresent invention.

Sincet-he catalytic method of combustion prevention or extinguishingdoesnot necessarilyi require'the use of fluids such as Water, it iseminently satisfactory for the extinguishing of oil fires asthere is notendency to spreadthe oil. I I f Whileall alkali forming metal compoundsare anti-combustion catalysts; some are better than othersand I havefound, for enample, that the phosphates, sulfates, chlorides andcarbonates of potassium and sodium'are v peculiarly effective. 'Alkalineearth metal compounds are'als'o effective and as'many of them areextremely cheap they present' some economic advantagesiiicertain casesqThe invention 'is, therefore, not limited to the use of the alkalimetals or 'sodium 'po- "'tassium compounds, although in its morespecific embodiments sodium and potassium compounds and particularlysodium potassium compounds of oxygen containing'acid' radicalsconstitutes asp'ecific' feature of the invention." "T

The invention ivill be described in greater detailin -connection With afew specific aX- f ainplesl V H E ample, '1. a:

Crude phtha'lic a'i'iyh dride frointhe .vapor phase oxidation. ofnaphthalene is treated with from 1min percent to 5% of potassium f,

s u lfate ii'liiclr should be incorporated in a, fined'er to" ienderquinonoid and similar impuri ties' non-volatile, and then sublimed ordis-' tilled off; Theoperation can be carried out Withcomplete safetyeven in an iron still Wh'ichmay be quite rusty, an importantconsi'd'eration because thus the cheapest kind of apparatus may-beutilized and it is-not nee-'1 essa y'toprovide linings orcoatings'ofmore 'corporatedwith them.

expensive. metals or of non-metallic sub stances It is also ofadvantageto inac tivate the walls of the-apparatus, for exam- I ple the refluxcondenserwhen, as "is usual,- the prolonged heating is 'carried outunder refluxing conditions, in order to v prevent catalytic combustion'from' taking place 7 Where surfaces contact with the vapors of if s ithe substancesand where;ssotcoursegthereis V v normally no,antiecoiiibustion catalyst.liig -:ln- J sbeadof using potassium siilfateotherizpo 1. tassium compounds, such as potassium chlo-i' ride oracidfphosphate'maybe used. "It is also possible to usesodium'compoundssuoh I as sodium sulfate, sodium .chloridefand the like.lVhen; such} substances are; used no @fire danger is encoui'iteredfin',discharging i'the" hot still residue and distillatio ican be ca ried out\VlthOllhQXCltlSlOjfOf Ema/ripple 2..

Coaltar is distilled after admixing aboiit halffa percent of potassium.carbonate' or l% of sodium chloride or sulfate-[with ftjh'c' j material.'7 There is l no-tendency to coinbus i tion even when the still isopened agate; f activity of the coke formed is dampedcand" neutralizedby the presence of the--ai'iticonr-j bustion catalyst: I m

V A crude naphthalenefraction.is subliined' in a stream of'ai-rafter'aboutfa quartei' t' 1%, of potassium b'isulf ate or 'onejhalfi' 32% ofsodiumbisulfate or'sulfatehasjbeenj added; Sublimationtakesplaceyvithoutifi danger and can be carriedto afiurther e 1 t f'r sd e s r w en bi Ct higher temperatures ;to vaporizefthe last-j e fe h nh el e ideis net Pre iti a fire' danger. "The walls'of theappa'ratus mayadyanta'geously be inactivated bytre at mentjvith potassium bisulfateiorpotassium p osph'ate or with the: corresponding sodium;

' cru e anthracene admixed j ifithfaboi t I l lialfito 11% ofs'odiu'm'for potassium sulfate 7Q it In the foregoing examples typicalprocesses have been illustrated involving the distillation andvaporization of combustis ble organic materials. It is known to purifysuch materials, and notably crude phthalic anhydride, by heating themwith condens ing agents in order to effect polymerization andcondensation of impurities, and for this purpose alkalies and othercompounds of alkali forming metals have been used. The present inventionis not concerned with the purification of such materials, and the use ofalkali forming metal compounds having properties which enable them toserve as condensing agents is hereby expressly disclaimed. It will bereadily appreciated that many alkali forming metal compounds which arenot condensing agents, such as sodium chloride and the like, are muchcheaper than even the cheapest condensing agents, and since foranti-combustion purposes they must be used in relatively largerquantities, the factor of cost is an important consideration.

This is in part a continuation of my copending application Serial No.196,893, filed June 3, 1927 now Patent 1,709,853, dated A ril Q3, 1929.

Vhat is claimed as new is:

1. An anti-combustion process, which comprises associating with crudefusible combustible material at least one alkali forming metal compoundwhich is not a condensing agent in amounts sufiicient to act as ananti-combustion catalyst, but insufficient to act as a smothering agent.

2. An anti-combustion process, which comprises associating with crudefusible combustible material at least one alkali metal compound which isnot a condensing agent in amounts suificient to act as ananti-combustion catalyst, but insufiicient to act as a smothering agent.

3. An anti-combustion process which comprises associating with crudefusible combustile material an alkali metal compound which is not acondensing agent in amounts from to 8% by weight of the combustiblematerial.

at. A method of preventing fires in the vaporization of crude organicmaterials, which comprises associating with the organic material to bevaporized a compound of an alkali metal which is not a condensing agentin amounts sufiicient to act as an anticombustion catalyst, hutinsufiicient to act as a smothering agent.

5. A method of preventing fires in the vaporization of crude organicmaterials, which comprises associating with the organic material to bevaporized a compound of an alkali metal which is not a condensing agentin amounts ranging from to 8% by weight of the material to be vaporized.

6. An anti-combustion process, which comprises associating sodiumchloride with crude fusible combustible material in amounts suiiicientto act as an anti-combustion catalyst, but insuiiicient to act as asmothering agent.

7. An anti-combustion ,process, which comprises associating sodiumchloride with crude fusible combustible material in amounts ranging fromto 8% by weight.

8. A method of preventing fires in the vaporization of crude organicmaterials which comprises associating sodium chloride with the organicmaterial in amounts sufiicient to act as an anti-combustion catalyst,but insutlicient to act as a smothering agent.

9. A method of preventing combustion processes of heating crude phthalicanhydride under vaporizing conditions, which comprises associating withthe crude phthalic anhydride an alkali metal compound which is not acondensing agent in amounts sufiicient to act an anti-combustioncatalyst, but insuiiicient to act as a smothering agent.

10. A method of preventing fires in the vaporization of organicmaterials, which comprises associating sodium chloride with crudeorganic material to be vaporized in amounts ranging from to 8% byweight.

11. A method of preventing combustion in the processes of heating crudephthalic anhydride under vaporizing conditions, which comprisesassociating sodium chloride with the crude phthalic anhydride in amountssufiicient to act as an anti-combustion catalyst, but insufficient toact as a smothering agent.

12. A method of preventing combustion in the processes of heating crudephthalic anhydride under vaporizing conditions, which comprisesassociating sodium chloride with the crude phthalic anhydride in amountsranging from to 5% by weight.

Signed at Pittsburgh, Pennsylvania this 6th day of July, 1928.

ALPHONS O. JAEGER.

